148 PROCEEDINGS OF THE CALIFORNIA 



December 23d, 7h. — A light shock at San Francisco. 



Of the whole number which have occurred during the year, two only have 

 been felt at San Francisco that were not experienced at other localities, and 

 four others have occurred which have been felt in common at other portions of 

 the State — thus making about one-third of the whole number that were in com- 

 mon here and elsewhere. 



Eight of the aggregate have occurred between the summer and winter sol- 

 stices. 



Seven have occurred during the spring and summer months, and ten during 

 the winter and autumn. 



Eight have occurred between the vernal and autumnal equinoxes. 



1858. 



During the past year we have had occasion to note the occurrence of eight 

 shocks of earthquake in this State. This number is one-half less than that in 

 1857, and one-third less the number in 1856. The shocks, with one exception, 

 have been unmarked by anything like violence, being little else than mere vibra- 

 tions or tremors, not noticeable by the great majority of the people. They are 

 as follows : 

 February 10th. — A smart shock at Kanaka Flat, Sierra County. No time 



noted. 

 February 15th, 4h. 20m.— A light shock in San Francisco. Was observed in 



the County of San Mateo ten miles south of the city. 

 August 19th, 22h. 10m. — A light shock in San Francisco. The motion was 



east to west, and was undulatory. 

 September 2d. — A smart shock at Santa Barbara, no time given. 

 September 3d, Oh. 40m. — A smart shock in San Jose. This shock was felt at 

 Santa Cruz, twenty -five miles west, and was evidently more marked in strength 

 at that locality. No damage. 

 September 12th, 19h. 40m. — A smart shock at San Francisco. The motion 

 was from north to south. There were two vibrations with undulatory move- 

 ments lasting about fifteen seconds. 

 September 26th, lh. 26m. — A light shock at San Francisco. 

 November 26th, Oh. 24m. — A heavy shock at San Francisco. This shock was 

 by far the heaviest during the year, it awoke most people from slumber and 

 created no little alarm ; persons left their beds and sought cooler situations 

 with less attire than is usually worn. The iron pillars in the second story of 

 the custom house have separated from the ceiling above about half an inch, 

 and are supposed to have settled from the effects of the shock ; I much doubt 

 the alleged cause of this displacement, as the pillars below present no indica- 

 tion of similar disturbance. This shock was felt at Oakland ten miles east of 

 the city, but was not felt at Stockton, Sacramento, nor Marysville. It was 

 evidently confined to an area of ten or twelve miles. 



